The Gunners captained penned terms to 2023 this week.
Arteta said, “I knew what was coming so I was relaxed.
"I'm really pleased to convince Auba to stay, with the terms as well. Also really pleased to see the reaction at Colney and with our fans.
“It's a joy to work with him. We have a really transparent relationship. The way he behaves and performs is exactly what I want. It took a lot of work so thank you for supporting us because it was key. It was worrying because it's hard to replace strikers of that calibre.
“I think the big reason Auba's staying is because we have an incredible football club. He feels how much love he's got from the fans. I played my part but the club and the people that have been able to put a package together for him to stay deserve credit."
He added: “The Premier League always has the best players in the world.
"Gareth is one of the most significant players.
“I think it's always positive to bring the best players back. The competition from every club is making this league harder and harder."